1010 electrons enter the emitter of a junction transistor in a time of 0.4µs. If 5% of the electrons are lost in the base, then the collector current is
Number of electrons entering emitter per second (or per given time) NE=1010‌ electrons in ‌t=0.4µs 5% of electrons are lost in the base. So, only 95% of electrons reach the collector. Step 1: Find the emitter current Total charge entering emitter in 0.4µs : QE=NE×e=1010×1.6×10−19=1.6×10−9C Emitter current: IE=‌
QE
t
=‌
1.6×10−9
0.4×10−6
=4.0mA Step 2: Find the collector current Since 5\% are lost, 95\% reach collector: IC=0.95IE=0.95×4.0mA=3.8mA Final Answer: IC=3.8mA Correct option: D ( 3.8 mA )